Abstract

Secretory IgA (s-IgA) antibody is locally synthesized and secreted following bacterial infections of mucosal surfaces (1–12). IgG, and to a lesser extent IgM antibody, have also been found in secretions following bacterial infections or immunization against bacterial infections, but it is s-IgA that predominates in such responses. These data all point to a prominent function of s-IgA in the protection of mucosal surfaces against bacterial infections. There have been several in vitro studies which have produced evidence that s-IgA might be able to protect against bacterial infection (13–16). Steele et al. (17) in the only in vivo study of the antibacterial effect reported that Vibrio cholerae organisms precoated with immune s-IgA were not able to produce disease in infant mice.